Dunlop played for Sandyford, Hurlford, Kilmarnock and Abercorn in Scotland[3][1] before being signed by Liverpool managers John McKenna and William Barclay in January 1895 for £35.

The left sided full-back would have enjoyed his second season a bit more as Liverpool gained promotion straight back to the First Division in 1895–96.

Dunlop's early appearances for the Reds were sporadic but his loyalty and dedication paid off as he was to become a regular starter over a 10-year period which included the Anfield club's first ever Football League Championship win in 1900–01, a feat they were to repeat in 1905–06 (after another relegation in 1903–04 followed by promotion 1904–05 in a turbulent period).

Having earlier been overlooked despite a strong performance in the Home Scots v Anglo-Scots trial match in 1901,[1] Dunlop earned one international cap when he represented Scotland against England on 7 April 1906, a game Scotland won 2–1 in a British Home Championship fixture at Hampden Park, Glasgow.

Dunlop's Liverpool teammate Alex Raisbeck also played in the match, captaining the Scots.